氮化钛膜电极的制备及对多巴胺的检测

Preparation of Titanium Nitride Film Electrode and Its Application for Determination of Dopamine

摘要: 采用阳极氧化法在抛光后的钛片表面制备了粗糙的TiO₂膜电极，经氨气氮化还原后将前驱体TiO₂转化为氮化钛(TiN)。XRD、SEM和EDS表征分析发现，850℃氮化处理后，氮化钛电极表面具有花状凸起结构，氮化钛的主要成分为Ti₂N和TiN，N元素的含量达到了32.14%。实验研究了多巴胺在该电极的电化学行为，发现TiN电极对多巴胺有良好的电催化作用。在0.1 M磷酸缓冲溶液中，采用计时电流法和差分脉冲伏安法测定了TiN电极对多巴胺的检出限，分别为1.3 μM和0.33 μM。在100 μM抗坏血酸存在下，TiN电极对多巴胺的检出限为0.56 μM。TiN电极具有较好的重现性。单个电极对25 μM DA重复测定5次，相对标准偏差(RSD)为3.97%；新制的4根膜电极在含25 μM DA的溶液中测试所得的相对标准偏差为4.2%。

Abstract: A roughened titanium nitride (TiN) film is fabricated on a polished Ti substrate through anodic oxidation process and subsequent nitridation in ammonia atmosphere. The composition and morphology were characterized by XRD, SEM and EDS. The results indicate that, after the nitriding process annealed at 850˚C, the surface of TiN film is of flower convex structure, with Ti₂N and TiN as the main nitride phase, and the content of N element (Atom%) reached 32.14%. Experiments have conducted to explore the electrochemical behavior of dopamine (DA) at TiN film. It is found that TiN film has good electrocatalytic activity for dopamine. Chronoamperometry and differential pulse voltammetry (DPV) were used to determine the detection limit of DA in 0.1 M phosphate buffer solution. The detection limits by two methods were calculated to be 1.3 μM and 0.33 μM. And the detection limit of DA in the presence of 100 μM ascorbic acid was calculated to be 0.56 μM. Furthermore, TiN film exhibits a good repeatability with the relative standard deviation (RSD) of 3.97% for 5 parallel detections in 25 μM dopamine using a single TiN electrode, and the RSD of 4 new electrodes is 4.2%.